Fluid-enhanced surface diffusion controls intraparticle phase transformations

Yiyang Li; Hungru Chen; Kipil Lim; Haitao D Deng; Jongwoo Lim; Dimitrios Fraggedakis; Peter M Attia; Sang Chul Lee; Norman Jin; Jože Moškon; Zixuan Guan; William E Gent; Jihyun Hong; Young-Sang Yu; Miran Gaberšček; M Saiful Islam; Martin Z Bazant; William C Chueh

doi:10.1038/s41563-018-0168-4

Fluid-enhanced surface diffusion controls intraparticle phase transformations

Nat Mater. 2018 Oct;17(10):915-922. doi: 10.1038/s41563-018-0168-4. Epub 2018 Sep 17.

Authors

Yiyang Li^{1

2

3}, Hungru Chen⁴, Kipil Lim^{1

5}, Haitao D Deng¹, Jongwoo Lim^{1

2}, Dimitrios Fraggedakis⁶, Peter M Attia¹, Sang Chul Lee¹, Norman Jin¹, Jože Moškon⁷, Zixuan Guan⁸, William E Gent⁹, Jihyun Hong^{1

5}, Young-Sang Yu¹⁰, Miran Gaberšček^{7

11}, M Saiful Islam¹², Martin Z Bazant^{13

14

15

16}, William C Chueh^{17

18}

Affiliations

¹ Department of Materials Science & Engineering, Stanford University, Stanford, CA, USA.
² Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, USA.
³ Sandia National Laboratories, Livermore, CA, USA.
⁴ Department of Chemistry, University of Bath, Bath, UK.
⁵ Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, USA.
⁶ Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA.
⁷ National Institute of Chemistry, Ljubljana, Slovenia.
⁸ Department of Applied Physics, Stanford University, Stanford, CA, USA.
⁹ Department of Chemistry, Stanford University, Stanford, CA, USA.
¹⁰ Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
¹¹ Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia.
¹² Department of Chemistry, University of Bath, Bath, UK. m.s.islam@bath.ac.uk.
¹³ Department of Materials Science & Engineering, Stanford University, Stanford, CA, USA. bazant@mit.edu.
¹⁴ Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA. bazant@mit.edu.
¹⁵ Department of Mathematics, Massachusetts Institute of Technology, Cambridge, MA, USA. bazant@mit.edu.
¹⁶ SUNCAT Interfacial Science and Catalysis, Stanford University, Stanford, CA, USA. bazant@mit.edu.
¹⁷ Department of Materials Science & Engineering, Stanford University, Stanford, CA, USA. wchueh@stanford.edu.
¹⁸ Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, USA. wchueh@stanford.edu.

PMID: 30224783
DOI: 10.1038/s41563-018-0168-4

Abstract

Phase transformations driven by compositional change require mass flux across a phase boundary. In some anisotropic solids, however, the phase boundary moves along a non-conductive crystallographic direction. One such material is Li_XFePO₄, an electrode for lithium-ion batteries. With poor bulk ionic transport along the direction of phase separation, it is unclear how lithium migrates during phase transformations. Here, we show that lithium migrates along the solid/liquid interface without leaving the particle, whereby charge carriers do not cross the double layer. X-ray diffraction and microscopy experiments as well as ab initio molecular dynamics simulations show that organic solvent and water molecules promote this surface ion diffusion, effectively rendering Li_XFePO₄ a three-dimensional lithium-ion conductor. Phase-field simulations capture the effects of surface diffusion on phase transformation. Lowering surface diffusivity is crucial towards supressing phase separation. This work establishes fluid-enhanced surface diffusion as a key dial for tuning phase transformation in anisotropic solids.

Publication types

Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.